Is there any law or rule covering air conditioning efficiency ratings?

Yes. The National Appliance Energy Conservation Act of 1987 (Public Law 100-12) sets national standards for residential air cooled central air conditioners and air source central heat pumps. The NAECA provides for a federal minimum standard of 10.0 seasonal energy efficiency ratio (SEER) for split system air conditioners and heat pumps, effective Jan. 1, 1992, and 9.7 SEER for single package air conditioners and heat pumps, effective Jan. 1, 1993. Heat pumps also are subject to federal standards of 6.8 heating seasonal performance factor (HSPF) for split systems, effective Jan. 1, 1992, and 6.6 HSPF for single packages, effective Jan. 1, 1993. ... more

Yes. The National Appliance Energy Conservation Act of 1987 (Public Law 100-12) sets national standards for residential air-cooled central air conditioners and air-source central heat pumps. The NAECA provides for a federal minimum standard of 10.0 seasonal energy efficiency ratio (SEER) for split-system air conditioners and heat pumps, effective Jan. 1, 1992, and 9.7 SEER for single-package air conditioners and heat pumps, effective Jan. 1, 1993. Heat pumps also are subject to federal standards of 6.8 heating seasonal performance factor (HSPF) for split systems, effective Jan. 1, 1992, and 6.6 HSPF for single packages, effective Jan. 1, 1993. ... more